The calculation shows the risk-neutral probability of an up move in a binomial tree model. Given:
- r = 12% annual interest rate
- Δt = 3/12 = 0.25 years
- u = 1.2 (up factor)
- d = 0.8 (down factor)
The formula for risk-neutral probability is:
Pup=u−derΔt−d
Substituting the values:
Pup=1.2−0.8e0.12×0.25−0.8=0.4e0.03−0.8=0.41.03045−0.8=0.40.23045=0.576125≈57.61%